My 1982 305 v8 berlinetta has a magnetic timing probe hole which sits on the harmonic balancer. The timing on it is slightly advanced and I am trying to get it back to the factory set timing. I own a tach-dwell magnetic timing tester (model 2950) and follow the directions in the manual to the hook-up chart...

I hook the clamps onto the battery and insert the "blue clip" into the negative coil on the distributor. I set the "probe holder offset figure" for digital magnetic timing to -9.5 for general motors. However this is where I am stuck. I have no idea where to go from there, or how much I am supposed to rotate the distributor to set my timing. If anyone has any knowledge of how to use magnetic timers or magnetic timing equipment that would be very helpful. Thanks!

 

What's your general location and altitude?

Why do you feel the timing currently is in need of "correction?"

It's pretty easy to hold a timing light over the peaks and valleys timing tab (usually visible behind the water pump on 80s models) to see timing.

Adjusting a degree or two isn't tough if you've disabled the advance via the harness disconnect wire (if present) or the dist. connector or the other method(s).

If your newfangled toy there helps you tell if you've changed timing 1.0 or 2.0 degrees advanced or retarded, that's all you need it to do. An 82 LG4 will generally run correctly on 0 degrees or a tiny bit of advance.

 

I would suggest not trying to outsmart yourself with something like that.

That's about the functional equivalent of using a quantum supercomputer to program the path of an ox-drawn farm cart. "Measure with micrometer, mark with chalk, cut with axe".

For one thing, the "mark" on your crank damper is on the OUTSIDE piece of it; the inertia ring, which is only loosely associated with the engine by a blob of spooge. They are NEVER accurate. For another, the entire mechanical linkage (chain, gears, etc.) responsible for that, is highly variable: your timing chain "stretches" and "tightens" substantially as RPMs change, as wear occurs, as it heats up and cools down, etc. There's FAR more "noise" in the ignition timing than most people realize.

Then there's the matter of the timing "spec" itself... it's not as though that number represents some sort of mechanical Nirvana, a state of perfection so sublime it will revolutionize the experience of driving the car, etc. It is a mish-mash of concerns that all interact, and was ultimately decided by some sort of committee (much as it could be said that a camel is a horse designed by a committee). It contains any number of compromises that may or may not be appropriate to YOU and YOUR car. As a typical example, it was based on the fuel that was available in 1982; it has not somehow revised itself to account for all the changes that have occurred since then (ethanol content for example). Worse still, the final ruling voice in that committee was the EMISSIONS point of view; next strongest was CAFE; next strongest was warranty cost mgmt.; and so on, down the list of the concerns of a NEW CAR mfr in 1982, which were (and are to this day) NOT the same as the owner of a NEW car, much less the owner of an antique like ours.

That's a nice instrument you got there. Box it up and store it safely against the opportunity to use it on something that needs that level of precision.

Adjust your ignition timing to where it runs the best, measure the result the best you can, and write that "number" down: that way you can put it back if it's ever disturbed. "Runs the best" might be any combination of some number of factors, based on how YOU like YOUR car to run where YOU live driving it for the uses YOU put it to on the roads YOU use with the fuel YOU can buy. Factors to include in your calculus might include greatest power output (which can only be achieved under ONE set of conditions), peppy throttle response, optimum running temperature, freedom from pinging, best fuel economy, and possibly even lowest emissions if you're in CA or something (in which case you'll need to be able to make the mark read right once every 2 years for inspection, whether that's actually "best" for the car or not), and others that may occur to you along the way.

Don't outsmart yourself. It's just a car; something very simple and commonplace and ordinary. 99.99999% of the cars that pass you on the highway won't have been adjusted with that level of technical sophistication, and even if yours is, they'll STILL be passing your car simply because ... your car can't help it.

Allow me to paraphrase one of The Greatest Ones in a completely unrelated field, who uttered a quote containing such an awesome amount of wisdom that it can be applied to almost anything:

"If it RUNS good, it IS good."

Nothing else matters. (with the occasional exception such as CA inspection and the like)

 

Nobody can answer "timing" questions on this forum any better than the "sofa"...lol!
I always take a look just for the entertainment provided

In all seriousness, OP, he is 100% correct.